CANBUS code works with one slave but seems to time out when I attach two slaves.

Using Arduino Programming Questions
1

So my CANBUS code works perfectly when I have one master and one slave but when I attach two slaves, the master receives data for 60-70 seconds then just stops. It of course starts working again when I restart the serial monitor. I am guessing something is being overloaded but I am not experienced enough to know what the exact problem is.

Here is my code for the two slaves. There are identical except for the address where one is 0x00 and the other is 0x10 (so 0 and 16).

// demo: CAN-BUS Shield, send data
#include <mcp_can.h>
#include <SPI.h>

void setup()
{
  Serial.begin(115200);
  // init can bus, baudrate: 500k
  if(CAN.begin(CAN_500KBPS) ==CAN_OK) Serial.print("can init ok!!\r\n");
  else Serial.print("Can init fail!!\r\n");
}


void loop()
{
  int sensor1 = analogRead(A1);
  sensor1 = map(sensor1, 0, 1023,0,255);
 
  int sensor2 = analogRead(A2);
  sensor2 = map(sensor2, 0, 1023,0,255);
  
  int sensor3 = analogRead(A3);
  sensor3 = map(sensor3, 0, 1023,0,255);
 
  unsigned char sensor1array[3]= {sensor1,sensor2,sensor3};
  
  Serial.println(sensor1,DEC);
  // send data:  id = 0x00, standrad flame, data len = 3, stmp: data buf
  CAN.sendMsgBuf(0x10, 0, 3, sensor1array);  
 // CAN.sendMsgBuf(0x10, 0, 1, sensor2array);  
  delay(100);                       // send data per 100ms
}

And here is my receiving code:

// demo: CAN-BUS Shield, receive data
#include <mcp_can.h>
#include <SPI.h>

unsigned char Flag_Recv = 0;
unsigned char len = 0;
unsigned char buf[3];



char str[20];

void setup()
{
  CAN.begin(CAN_500KBPS);                       // init can bus : baudrate = 500k
  attachInterrupt(0, MCP2515_ISR, FALLING);     // start interrupt
  Serial.begin(115200);
}

void MCP2515_ISR()
{
    Flag_Recv = 1;
}

void loop()
{
  
    if(Flag_Recv)                           // check if get data
    {
      Flag_Recv = 0;                        // clear flag
      CAN.readMsgBuf(&len, buf);            // read data,  len: data length, buf: data buf

      int address = CAN.getCanId();
      Serial.println(address);
      
      if (address == 0 )
{      
      Serial.print("Voltage at pin 1 is "); 
      float voltage1 = buf[0] * (5.1/ 255.0);
      Serial.println(voltage1);  
               
      Serial.print("Voltage at pin 2 is "); 
      float voltage2 = buf[1]  * (5.1/ 255.0);
      Serial.println(voltage2);
      
  /*    Serial.print("Arduino 2 value is  "); 
      float voltage3 = buf[3]* (5.1/ 255.0) ;
      Serial.println(voltage3);*/
}

else if (address ==1)
{
  Serial.println(buf[0]);
  Serial.print("Slave 2 going throug");
}
  Serial.println();
    }
}

I am using the MCP2551 and MCP2515 for the Canbus system and the line is terminated by 120 ohms on both sides. Thanks

2

And here is the other sending code. Like I said, it's the same except for the address in CAN.sendMsgBuf.

// demo: CAN-BUS Shield, send data
#include <mcp_can.h>
#include <SPI.h>

void setup()
{
  Serial.begin(115200);
  // init can bus, baudrate: 500k
  if(CAN.begin(CAN_500KBPS) ==CAN_OK) Serial.print("can init ok!!\r\n");
  else Serial.print("Can init fail!!\r\n");
}

void loop()
{
  int sensor1 = analogRead(A1);
  sensor1 = map(sensor1, 0, 1023,0,255);
 
  int sensor2 = analogRead(A2);
  sensor2 = map(sensor2, 0, 1023,0,255);
  
  int sensor3 = analogRead(A3);
  sensor3 = map(sensor3, 0, 1023,0,255);
 
  unsigned char sensor1array[3]= {sensor1,sensor2,sensor3};

  
  Serial.println(sensor1,DEC);
  // send data:  id = 0x00, standrad flame, data len = 3, stmp: data buf
  CAN.sendMsgBuf(0x00, 0, 3, sensor1array);  
 
  delay(100);                       // send data per 100ms
}
3

So just in case somebody else has this problem, turning down the canbus speed to 100k fixed the problem. The Serial speed wasn't fast enough to keep up and would just freeze.

4